Upper parts generally ochraceous; venter frequently buffy; size
small to medium; zygomatic arches usually appressed to cranium;
frequently difficult to distinguish from _E. minimus_.
Baculum: Shaft thin; keel low, 1/5 of length of tip; tip 30 to 35 per
cent of length of shaft; angle formed by tip and shaft 130 deg.; distal 1/5
of shaft slightly compressed laterally; shaft short, 2.37 to 2.96 mm.
Differs from _E. speciosus_, _E. panamintinus_, _E. umbrinus_, _E.
palmeri_, and _E. bulleri_, in base not markedly widened, shaft thinner;
from _E. quadrivittatus_, _E. ruficaudus_, _E. cinereicollis_ and _E.
quadrimaculatus_, in shaft thinner, baculum usually shorter, tip
shorter; from _E. dorsalis_, in keel lower, angle formed by tip and
shaft 130 deg., usually smaller; from _E. merriami_, in being markedly
shorter, and in base not being dorsally incised, tip proportionally
longer.
For comparisons with _E. alpinus_, _E. minimus_, _E. townsendii_, and
_E. sonomae_, see the accounts of those species.
Bacula from skins labeled as _E. amoenus amoenus_ from, Lardo, Valley
Co., Idaho (MM), Butte Co., Idaho (MM), and Boise National Forest, Idaho
(BS), resemble the bacula of _E. umbrinus_, and critical study of other
features of these specimens probably will show that they are _E.
umbrinus_.
_Specimens examined_: 23.
_E. amoenus amoenus_: Oregon: _Klamath Co._: Fort Klamath, 1
(MM). Idaho: _Valley Co._: Lardo, 1 (BS). _Butte Co._:
Unspecified, 1 (MM). Boise National Forest, 1 (BS).
_E. a. ludibundus_: British Columbia: Moose Lake, 1 (NM).
_E. a. luteiventris_: Alberta: Banff, 2 (BS). Montana: _Flathead
Co._: 1 mi. W and 2 mi. S Summit, 5,000 ft., 1. _Teton Co._:
17-1/8 mi. W and 6-1/2 mi. N Augusta, 5,100 ft., 2. _Missoula
Co._: Unspecified, 1 (MM). Idaho: _Idaho Co._: 20 mi. S and 2
mi. E Grangeville, 2. _Fremont Co._: 7 mi. W West Yellowstone,
7,000 ft., 5; 9 mi. SW West Yellowstone, 8,500 ft., 1. Wyoming:
_Teton Co._: 2-1/2 mi. N and 3-1/2 mi. E Moran, 7,225 ft., 1.
_E. a. monoensis_: California: _Mono Co._: Leevining Creek, 1
(NM).
_E. a. vallicola_: Montana: _Ravalli Co._: Bass Creek, 3-1/2 mi.
NW Stevensville, 3,750 ft., 2.
#Eutamias dorsalis# (Baird)